Question: $\dfrac{7}{8} - \dfrac{1}{5} = {?}$
Solution: $ = {\dfrac{7 \times 5}{8 \times 5}} - {\dfrac{1 \times 8}{5 \times 8}} $ $ = {\dfrac{35}{40}} - {\dfrac{8}{40}} $ $ = \dfrac{{35} - {8}}{40} $ $ = \dfrac{27}{40}$